US20170356293A1 - Balancing weight for a rotor blade of a turbine stage - Google Patents
Balancing weight for a rotor blade of a turbine stage Download PDFInfo
- Publication number
- US20170356293A1 US20170356293A1 US15/617,112 US201715617112A US2017356293A1 US 20170356293 A1 US20170356293 A1 US 20170356293A1 US 201715617112 A US201715617112 A US 201715617112A US 2017356293 A1 US2017356293 A1 US 2017356293A1
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- United States
- Prior art keywords
- fastening portion
- balancing weight
- rotor blade
- shroud
- bent
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Abandoned
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Classifications
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
- F01D—NON-POSITIVE DISPLACEMENT MACHINES OR ENGINES, e.g. STEAM TURBINES
- F01D5/00—Blades; Blade-carrying members; Heating, heat-insulating, cooling or antivibration means on the blades or the members
- F01D5/02—Blade-carrying members, e.g. rotors
- F01D5/027—Arrangements for balancing
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F05—INDEXING SCHEMES RELATING TO ENGINES OR PUMPS IN VARIOUS SUBCLASSES OF CLASSES F01-F04
- F05D—INDEXING SCHEME FOR ASPECTS RELATING TO NON-POSITIVE-DISPLACEMENT MACHINES OR ENGINES, GAS-TURBINES OR JET-PROPULSION PLANTS
- F05D2220/00—Application
- F05D2220/30—Application in turbines
- F05D2220/32—Application in turbines in gas turbines
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F05—INDEXING SCHEMES RELATING TO ENGINES OR PUMPS IN VARIOUS SUBCLASSES OF CLASSES F01-F04
- F05D—INDEXING SCHEME FOR ASPECTS RELATING TO NON-POSITIVE-DISPLACEMENT MACHINES OR ENGINES, GAS-TURBINES OR JET-PROPULSION PLANTS
- F05D2230/00—Manufacture
- F05D2230/60—Assembly methods
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F05—INDEXING SCHEMES RELATING TO ENGINES OR PUMPS IN VARIOUS SUBCLASSES OF CLASSES F01-F04
- F05D—INDEXING SCHEME FOR ASPECTS RELATING TO NON-POSITIVE-DISPLACEMENT MACHINES OR ENGINES, GAS-TURBINES OR JET-PROPULSION PLANTS
- F05D2240/00—Components
- F05D2240/20—Rotors
- F05D2240/30—Characteristics of rotor blades, i.e. of any element transforming dynamic fluid energy to or from rotational energy and being attached to a rotor
- F05D2240/303—Characteristics of rotor blades, i.e. of any element transforming dynamic fluid energy to or from rotational energy and being attached to a rotor related to the leading edge of a rotor blade
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F05—INDEXING SCHEMES RELATING TO ENGINES OR PUMPS IN VARIOUS SUBCLASSES OF CLASSES F01-F04
- F05D—INDEXING SCHEME FOR ASPECTS RELATING TO NON-POSITIVE-DISPLACEMENT MACHINES OR ENGINES, GAS-TURBINES OR JET-PROPULSION PLANTS
- F05D2240/00—Components
- F05D2240/20—Rotors
- F05D2240/30—Characteristics of rotor blades, i.e. of any element transforming dynamic fluid energy to or from rotational energy and being attached to a rotor
- F05D2240/304—Characteristics of rotor blades, i.e. of any element transforming dynamic fluid energy to or from rotational energy and being attached to a rotor related to the trailing edge of a rotor blade
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F05—INDEXING SCHEMES RELATING TO ENGINES OR PUMPS IN VARIOUS SUBCLASSES OF CLASSES F01-F04
- F05D—INDEXING SCHEME FOR ASPECTS RELATING TO NON-POSITIVE-DISPLACEMENT MACHINES OR ENGINES, GAS-TURBINES OR JET-PROPULSION PLANTS
- F05D2260/00—Function
- F05D2260/30—Retaining components in desired mutual position
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02T—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
- Y02T50/00—Aeronautics or air transport
- Y02T50/60—Efficient propulsion technologies, e.g. for aircraft
Definitions
- the present invention relates to a balancing weight for a rotor blade of a turbine stage of a gas turbine, in particular of an aircraft gas turbine; including a first bent fastening portion that is couplable to an axial leading edge of a shroud of the rotor blade, a second fastening portion that is couplable to an axial trailing edge of the shroud, and a middle portion that joins the first fastening portion and the second fastening portion.
- the wording “balancing weight for a rotor blade” means in particular that the balancing weight is suited for attachment to the rotor blade.
- Directional indications such as “axial,” “radial” and “circumferential” are to be basically understood as relative to the machine axis or the main flow direction of the gas turbine, unless otherwise explicitly or implicitly derived from the context.
- attaching balancing weights is also a complicated operational step because it requires introducing tools into the intermediate spaces between the rotor blades of a rotor blade ring in order to fasten the balancing weight. There is a risk of damage to the rotor blades.
- the second fastening portion assume a first position relative to the first fastening portion prior to a mounting of the balancing weight on the rotor blade, and a second position relative to the first fastening portion following the mounting of the balancing weight on the rotor blade; in the second relative position, the middle portion or/and the second fastening portion being deformed, in particular plastically deformed.
- the balancing weight is configured to allow the second fastening portion to be deformed relative to the first bent fastening portion from an initial position into a mounting position.
- the initial position (first relative position) thereby connotes a state of the balancing weight prior to the attachment thereof to the rotor blade shroud.
- the coupling between the second fastening portion and the shroud segment, in particular to the axially trailing shroud edge thereof, is accomplished by the deformation of the second fastening portion, respectively the middle portion.
- the first fastening portion may be bent to allow it to be hooked onto the axial leading edge of the shroud and, in the hooked-on state, be secured to the shroud at least in the radial and circumferential directions.
- the first fastening portion is bent in a hook or U-shape, for example, or in another suitable way that makes possible the desired hooking-on that may also be understood as a type of interlocking connection.
- hooking on is not necessarily to be understood as the first fastening portion resting under the force of gravity in a hanging manner, rather such a hooking on of the bent first fastening portion may also be realized along the axial direction.
- the hooking on may also be understood as bringing into engagement.
- the balancing weight may also be in the form of a strip-type metal element; the strip-type metal element having a plurality of bent regions along its extent from a first end to a second end.
- the first end may thereby be an unattached end of the first fastening portion, and the second end an unattached end of the second fastening portion.
- at least the fastening portion has one or a plurality of bent regions or portions.
- the second fastening portion may also have bent regions or portions.
- the second fastening portion may have bent regions that, themselves, are not deformed at the transition from the first relative position to the second relative position.
- the middle portion may have a torsion portion where the strip-type metal element is twisted about the longitudinal axis thereof in a first rotational direction, in particular by about 90°. In other words, it may be said that the middle portion is wound by about 90° along the longitudinal axis of the strip.
- the middle portion in relation to the second relative position of the second fastening portion, may be twisted about the longitudinal axis of the strip in a second rotational direction opposite the first rotational direction in a way that essentially flattens the torsion portion.
- the twisted torsion region is untwisted, so that there is no longer a turn in the middle portion.
- the middle portion When the middle portion is again essentially in a flat form in the second relative position of the second fastening portion, it may engage on a radial inner side of the shroud segment such that it extends on the shroud segment along a side of the respective rotor blade.
- the second fastening portion may have a plurality of elongated openings that are spaced at regular intervals, starting from an unattached end of the second fastening portion.
- the elongated openings may essentially extend here parallel to a bending axis, about which the second fastening portion is plastically deformed in the second relative position.
- the elongated openings are used, in particular, to facilitate the deformation or bending of the second fastening portion, since only a small amount of material of the second fastening portion to the side of the elongated openings needs to be deformed.
- a blade coupling portion which is configured to be couplable to a leading edge of the rotor blade, may adjoin the first fastening portion. Such a blade coupling portion is thereby used, in particular, to axially secure the balancing weight.
- a rotor blade ring of a turbine stage of a gas turbine in particular of an aircraft gas turbine, having a plurality of circumferentially adjacently disposed rotor blades which, at the radially outer ends thereof, have a respective shroud segment having an axially leading shroud edge and an axially trailing shroud edge; a balancing weight being disposed on at least one rotor blade on the shroud segment thereof, preferably a balancing weight of the previously described type; the balancing weight including a first bent fastening portion, which is coupled to the axially leading shroud edge, a second fastening portion that is coupled to the axially trailing shroud edge, and a middle portion that joins the first bent fastening portion and the second fastening portion.
- the second fastening portion thereby assumes a first position relative to the first fastening portion prior to a mounting of the balancing weight on the rotor blade, and a second position relative to the first fastening portion subsequently to the mounting of the balancing weight on the rotor blade; in the second relative position, the middle portion or/and the second fastening portion being deformed, in particular plastically deformed.
- the rotor blade ring preferably includes a multiplicity of individual blades or is even exclusively formed therefrom; a balancing weight of the type under discussion preferably being in contact with only one individual blade, not, however, with a plurality thereof.
- the balancing weight preferably does not extend past a shroud gap between two circumferentially adjacent individual blades.
- the advantage is derived that the balancing weight is able to be reliably held even when different creep elongations of the individual blades occur during operation.
- the balancing weight is preferably configured to be mountable without contacting the trailing edge of a blade in the rotor blade ring associated therewith.
- relatively brittle materials such as a TiAl-based material
- the balancing weight according to the present invention is not braced against the sensitive trailing edge, damage thereto may be reliably prevented. Instead, the plastic deformation of the inventive balancing weight at the axial rear end thereof during mounting allows it to be interlockingly coupled to the shroud of the rotor blade.
- the shroud preferably features a setback in the axial direction at the coupling location provided for that purpose.
- the balancing weight may have another unattached end, which, in the installed state of the balancing weight, preferably extends circumferentially on the side of the shroud facing away from the blade, respectively the airfoil portion, toward the trailing edge of the blade, respectively the airfoil portion.
- the mass of the balancing weight may be positioned relatively closely to the blade, respectively the airfoil portion. This has the advantage of making it possible to reduce unwanted deformations of the shroud when the centrifugal forces act on the balancing weight and the shroud.
- the present invention also relates to a method for attaching a balancing weight to a shroud segment of a rotor blade of a rotor blade ring of a turbine stage of a gas turbine that includes the following steps:
- FIG. 1 is a simplified, schematic, perspective view, axially from the front, of a rotor blade portion having the associated shroud and a balancing weight attached thereto.
- FIG. 2 is a simplified, schematic, perspective view of the balancing weight from FIG. 1 , prior to installation on the or a rotor blade.
- FIG. 3 is a simplified, schematic, perspective view, axially from the rear, of the rotor blade portion of FIG. 1 , including the associated shroud and the balancing weight attached thereto.
- FIG. 4 is a simplified, schematic, perspective view, axially from the rear, of a rotor blade portion having the associated shroud and an alternative balancing weight attached thereto.
- FIG. 5 is a simplified, schematic, perspective view, axially from the rear, of a rotor blade portion having the associated shroud and an alternative balancing weight attached thereto.
- FIG. 6 is a simplified, schematic, perspective view, axially from the front, of a rotor blade portion having the associated shroud and a balancing weight attached thereto.
- FIG. 7 is an axially rear fastening portion of a balancing weight.
- FIG. 8 is a type of perspective part sectional view of a balancing weight on a rotor blade, the balancing weight having an axially rear fastening portion in correspondence with FIG. 6 .
- FIG. 1 shows a radially outer portion of a rotor blade 10 and a shroud 12 associated therewith.
- Shroud 12 features an axial projection 14 .
- Projection 14 is configured in the area of axial leading edge 15 of rotor blade 10 .
- a first fastening portion 16 of a balancing weight 18 is hooked onto the radial outer side of projection 14 .
- first fastening portion 16 is repeatedly bent, and then merges into a middle portion 22 .
- Middle portion 22 extends along the shroud and along the suction side of rotor blade 10 .
- FIG. 2 shows balancing weight 18 of FIG. 1 in a simplified, perspective view.
- balancing weight 18 features a second fastening portion 24 .
- second fastening portion 24 is situated axially to the rear in each particular case and is couplable to an axial trailing edge of a shroud.
- middle portion 22 is twisted along axial direction AD (longitudinal direction of strip-type middle portion 22 ), here, exemplarily by approximately 90°. This twisted region 26 may also be referred to as torsion region 26 .
- Middle portion 22 essentially extends along axial direction AD.
- First fastening portion essentially extends along circumferential direction CD.
- Second fastening portion 24 essentially extends in radial direction RD.
- second fastening portion 24 is situated in a first position relative to first fastening portion 16 .
- Second fastening portion 24 assumes this first relative position when the balancing weight is not yet fastened to the shroud of the rotor blade.
- FIG. 2 shows an uninstalled state of balancing weight 18 .
- balancing weight 18 features the configuration shown in FIG. 2 prior to the mounting thereof on a rotor blade.
- FIG. 3 shows rotor blade 10 of FIG. 1 in a simplified, perspective view, axially from the rear.
- middle portion 22 of balancing weight 18 no longer shows a twisted region 26 .
- second fastening portion 24 has been swiveled clockwise relative to the direction of view in FIG. 2 and FIG. 3 .
- This swiveling or twisting moves second fastening portion 24 into a second position relative to first fastening portion 18 (not visible in FIG. 3 ). In this second relative position, second fastening portion 24 is coupled to an axial trailing edge 28 of shroud 12 .
- a balancing weight 18 is axially introduced by first fastening portion 16 thereof between two rotor blades and, specifically, axially from the rear. First fastening portion 18 is then hooked onto axial leading edge 15 of shroud 12 , in particular onto projection 14 . Upon positioning of first fastening portion 18 , middle portion 22 may be guided along shroud 12 . Second fastening portion 24 is then still situated in the first position illustrated in FIG. 2 relative to first fastening portion 16 . In the region of axial trailing edge 28 of shroud 12 , second fastening portion 24 may then be grasped by a suitable tool and twisted accordingly.
- Twisted region 26 of middle portion ( FIG. 2 ) is again opened, respectively middle portion 22 is again brought into an essentially torsion-free, respectively planar orientation ( FIG. 3 ).
- a balancing weight of this kind may be readily introduced along a rotor blade and fastened to the shroud of the rotor blade by a deformation of the balancing weight; in the present example, by a deformation of the middle portion.
- first fastening portion 16 is formed in a way that allows balancing weight 18 to be secured in radial direction RD, circumferential direction CD and axial direction AD.
- second fastening portion 24 In second position thereof relative to first fastening portion 16 , second fastening portion 24 additionally secures the balancing weight in axial direction AD and in radial direction RD.
- balancing weight 18 is securely installed on shroud 12 .
- FIG. 4 shows an illustration similar to that of FIG. 3 ; in addition to second fastening portion 24 , which is likewise illustrated here in the second position relative to first fastening portion 16 , balancing weight 18 featuring a securing portion 30 .
- Additional securing portion 30 constitutes a securing in axial direction AD and rests against axial trailing edge 28 of shroud 12 .
- securing portion 30 and second fastening portion 24 form two side portions that extend slightly obliquely relative to each other starting from middle portion 22 .
- FIG. 5 shows an illustration similar to that of FIG. 4 ; in the case of balancing weight 18 , securing portion 30 and second fastening portion 24 having a continuous design along trailing edge 28 of shroud 12 .
- securing portion 30 also serves as securing in axial direction AD.
- balancing weight 18 may likewise feature a twisted region 26 in an uninstalled state, analogously to the balancing weight in FIG. 2 .
- balancing weights of FIGS. 4 and 5 it may be considered that only second fastening portion 24 is bent downwardly in the first relative position and, in the case of installation, bent correspondingly upwardly.
- FIG. 6 shows an illustration similar to that of FIG. 1 ; adjoining first fastening portion 16 on balancing weight 18 , a hook-on portion 32 (blade coupling portion) being provided that is positioned in the region of an axial leading edge of rotor blade 10 .
- This hook-on portion 32 provides securing in axial direction AD and circumferential direction CD, while first fastening portion 16 is used for securing balancing weight 18 in axial direction AD and radial direction RD.
- first fastening portion 16 is bent around leading edge 15 of the shroud and not looped around projection 14 , as in FIG. 1 .
- FIG. 7 shows an alternative second fastening portion 24 of a balancing weight.
- second fastening portion In a first position thereof relative to first fastening portion, second fastening portion is essentially planar in accordance with FIG. 7A .
- the second fastening portion features elongated holes or slots 36 that extend transversely to the longitudinal extent thereof If a balancing weight having such a second fastening portion 24 is attached to the shroud of a rotor blade, the second fastening portion may be deformed or bent over in the area of elongated holes 36 once the balancing weight is introduced, and the first fastening portion is hooked on, allowing it to be bent around axial trailing edge ( 28 ) ( FIG. 1, 3, 4, 5 ) of the shroud.
- the bending process is illustrated step by step in FIGS. 7B and 7C .
- the process of deforming or bending second fastening portion 24 is simplified due to the structural weakening of the otherwise strip-type fastening portion 24 .
- second fastening portion 24 has been bent over or deformed twice in the second relative position.
- second fastening portion assumes a different relative position than in first relative position ( FIG. 7A ).
- a web 38 is formed between the two elongated holes 36 .
- this web 38 may be adapted to the contour along an axial trailing edge 28 of the shroud.
- web 38 is deformed in axial direction AD toward the trailing edge of shroud 12 , allowing it to rest against the multiply curved contour of the shroud. This makes it possible to form a type of interlocking connection.
- second fastening portion in FIG. 8 is merely depicted as a stylized sectional view to provide a better illustration of deformed web 38 .
- middle portion 22 is actually joined to second fastening portion 24 , even when this is not shown in FIG. 8 .
- balancing weight 18 of FIG. 8 has a design similar to that of FIG. 6 and features a hook-on portion 32 .
- Balancing weight 18 presented here generally has a type of metallic strip design; as is apparent in FIG. 2 , this strip being bent or deformed in different directions, so that the various portions are formed that are then used for mounting on the shroud.
- balancing weight 18 shown with reference to FIG. 1 through 8 in particular of the various embodiments of fastening portions 16 , 24 or of the further portions, such as securing portion 30 or hook-on portion 32 or middle portion 22 , with or without twisted region 26 , may be combined with one another in any way desired.
- a first fastening portion 16 shown in FIG. 1 that is hooked onto a projection 14 of shroud 12 , may feature a second fastening portion 24 in accordance with FIG. 7 .
- Every combination that is derivable from the figures leads to a further specific embodiment of the balancing weight according to the present invention, even when all possible combinations are not explicitly shown.
- the balancing weight presented here makes possible altogether a simple mounting of the balancing weight along a rotor blade and on the shroud of this one rotor blade; it being necessary to deform the middle portion or/and the second fastening portion, respectively, for final completion of the fastening to bring the second fastening portion into the second position thereof relative to the first fastening portion.
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Abstract
Description
- This claims the benefit of German Patent Application DE 102016210454.3, filed Jun. 14, 2016 and hereby incorporated by reference herein.
- The present invention relates to a balancing weight for a rotor blade of a turbine stage of a gas turbine, in particular of an aircraft gas turbine; including a first bent fastening portion that is couplable to an axial leading edge of a shroud of the rotor blade, a second fastening portion that is couplable to an axial trailing edge of the shroud, and a middle portion that joins the first fastening portion and the second fastening portion. In this instance, the wording “balancing weight for a rotor blade” means in particular that the balancing weight is suited for attachment to the rotor blade.
- Directional indications, such as “axial,” “radial” and “circumferential” are to be basically understood as relative to the machine axis or the main flow direction of the gas turbine, unless otherwise explicitly or implicitly derived from the context.
- It is generally known to provide a balancing weight in the region of two adjacent shroud segments, the balancing weight extending over both shroud segments. The disadvantage of such a balancing weight configuration is that the two adjacent shroud segments are subject to relative movements, hereby also altering the position of the balancing weight and producing unfavorable stress ratios, or even loosening an attachment of the balancing weight over time, which can disadvantageously lead to fretting.
- Generally, attaching balancing weights is also a complicated operational step because it requires introducing tools into the intermediate spaces between the rotor blades of a rotor blade ring in order to fasten the balancing weight. There is a risk of damage to the rotor blades.
- It is an object of the present invention to provide a balancing weight that will overcome the above-mentioned disadvantages.
- To achieve this objective, it is provided that the second fastening portion assume a first position relative to the first fastening portion prior to a mounting of the balancing weight on the rotor blade, and a second position relative to the first fastening portion following the mounting of the balancing weight on the rotor blade; in the second relative position, the middle portion or/and the second fastening portion being deformed, in particular plastically deformed.
- Thus, the balancing weight is configured to allow the second fastening portion to be deformed relative to the first bent fastening portion from an initial position into a mounting position. The initial position (first relative position) thereby connotes a state of the balancing weight prior to the attachment thereof to the rotor blade shroud. In the mounting position, where the first bent portion is coupled to the leading axial shroud edge, the coupling between the second fastening portion and the shroud segment, in particular to the axially trailing shroud edge thereof, is accomplished by the deformation of the second fastening portion, respectively the middle portion.
- The first fastening portion may be bent to allow it to be hooked onto the axial leading edge of the shroud and, in the hooked-on state, be secured to the shroud at least in the radial and circumferential directions. The first fastening portion is bent in a hook or U-shape, for example, or in another suitable way that makes possible the desired hooking-on that may also be understood as a type of interlocking connection. It should be appreciated that the term “hooking on” is not necessarily to be understood as the first fastening portion resting under the force of gravity in a hanging manner, rather such a hooking on of the bent first fastening portion may also be realized along the axial direction. The hooking on may also be understood as bringing into engagement.
- The balancing weight may also be in the form of a strip-type metal element; the strip-type metal element having a plurality of bent regions along its extent from a first end to a second end. The first end may thereby be an unattached end of the first fastening portion, and the second end an unattached end of the second fastening portion. As already explained above, at least the fastening portion has one or a plurality of bent regions or portions. However, in the first or/and the second relative position, the second fastening portion may also have bent regions or portions. In particular, the second fastening portion may have bent regions that, themselves, are not deformed at the transition from the first relative position to the second relative position.
- In relation to the first relative position of the second fastening portion, the middle portion may have a torsion portion where the strip-type metal element is twisted about the longitudinal axis thereof in a first rotational direction, in particular by about 90°. In other words, it may be said that the middle portion is wound by about 90° along the longitudinal axis of the strip.
- Moreover, in relation to the second relative position of the second fastening portion, the middle portion may be twisted about the longitudinal axis of the strip in a second rotational direction opposite the first rotational direction in a way that essentially flattens the torsion portion. Thus, in the second relative position, the twisted torsion region is untwisted, so that there is no longer a turn in the middle portion. When the middle portion is again essentially in a flat form in the second relative position of the second fastening portion, it may engage on a radial inner side of the shroud segment such that it extends on the shroud segment along a side of the respective rotor blade.
- The second fastening portion may have a plurality of elongated openings that are spaced at regular intervals, starting from an unattached end of the second fastening portion. In addition, the elongated openings may essentially extend here parallel to a bending axis, about which the second fastening portion is plastically deformed in the second relative position. The elongated openings are used, in particular, to facilitate the deformation or bending of the second fastening portion, since only a small amount of material of the second fastening portion to the side of the elongated openings needs to be deformed.
- A blade coupling portion, which is configured to be couplable to a leading edge of the rotor blade, may adjoin the first fastening portion. Such a blade coupling portion is thereby used, in particular, to axially secure the balancing weight.
- Another aspect of the present invention relates to a rotor blade ring of a turbine stage of a gas turbine, in particular of an aircraft gas turbine, having a plurality of circumferentially adjacently disposed rotor blades which, at the radially outer ends thereof, have a respective shroud segment having an axially leading shroud edge and an axially trailing shroud edge; a balancing weight being disposed on at least one rotor blade on the shroud segment thereof, preferably a balancing weight of the previously described type; the balancing weight including a first bent fastening portion, which is coupled to the axially leading shroud edge, a second fastening portion that is coupled to the axially trailing shroud edge, and a middle portion that joins the first bent fastening portion and the second fastening portion. The second fastening portion thereby assumes a first position relative to the first fastening portion prior to a mounting of the balancing weight on the rotor blade, and a second position relative to the first fastening portion subsequently to the mounting of the balancing weight on the rotor blade; in the second relative position, the middle portion or/and the second fastening portion being deformed, in particular plastically deformed. The rotor blade ring preferably includes a multiplicity of individual blades or is even exclusively formed therefrom; a balancing weight of the type under discussion preferably being in contact with only one individual blade, not, however, with a plurality thereof. In particular, the balancing weight preferably does not extend past a shroud gap between two circumferentially adjacent individual blades. Here, the advantage is derived that the balancing weight is able to be reliably held even when different creep elongations of the individual blades occur during operation.
- Furthermore, the balancing weight is preferably configured to be mountable without contacting the trailing edge of a blade in the rotor blade ring associated therewith. In applications in the high-temperature region, in particular, relatively brittle materials, such as a TiAl-based material, are preferably used as a blade base material. Since the trailing edge of such a blade is generally relatively thin compared to the leading edge, it is correspondingly sensitive to load effects. Because the balancing weight according to the present invention is not braced against the sensitive trailing edge, damage thereto may be reliably prevented. Instead, the plastic deformation of the inventive balancing weight at the axial rear end thereof during mounting allows it to be interlockingly coupled to the shroud of the rotor blade. The shroud preferably features a setback in the axial direction at the coupling location provided for that purpose. On the second fastening portion thereof, the balancing weight may have another unattached end, which, in the installed state of the balancing weight, preferably extends circumferentially on the side of the shroud facing away from the blade, respectively the airfoil portion, toward the trailing edge of the blade, respectively the airfoil portion. Thus, viewed circumferentially, the mass of the balancing weight may be positioned relatively closely to the blade, respectively the airfoil portion. This has the advantage of making it possible to reduce unwanted deformations of the shroud when the centrifugal forces act on the balancing weight and the shroud.
- Finally, the present invention also relates to a method for attaching a balancing weight to a shroud segment of a rotor blade of a rotor blade ring of a turbine stage of a gas turbine that includes the following steps:
- providing a balancing weight having a first bent fastening portion, a second fastening portion, and a middle portion that joins the first fastening portion and the second fastening portion;
- introducing the first bent fastening portion and the middle portion between two adjacent rotor blades of the rotor blade ring in a flow direction opposite that of the gas turbine;
- positioning the first bent fastening portion on an axially leading edge of the shroud segment and coupling it thereto, in particular by hooking on the first bent fastening portion;
- deforming the second fastening portion or/and the middle portion, allowing the second fastening portion to be coupled to an axially trailing edge of the shroud segment.
- The present invention will be explained exemplarily in the following with reference to the enclosed figures and without being limited thereto.
-
FIG. 1 is a simplified, schematic, perspective view, axially from the front, of a rotor blade portion having the associated shroud and a balancing weight attached thereto. -
FIG. 2 is a simplified, schematic, perspective view of the balancing weight fromFIG. 1 , prior to installation on the or a rotor blade. -
FIG. 3 is a simplified, schematic, perspective view, axially from the rear, of the rotor blade portion ofFIG. 1 , including the associated shroud and the balancing weight attached thereto. -
FIG. 4 is a simplified, schematic, perspective view, axially from the rear, of a rotor blade portion having the associated shroud and an alternative balancing weight attached thereto. -
FIG. 5 is a simplified, schematic, perspective view, axially from the rear, of a rotor blade portion having the associated shroud and an alternative balancing weight attached thereto. -
FIG. 6 is a simplified, schematic, perspective view, axially from the front, of a rotor blade portion having the associated shroud and a balancing weight attached thereto. -
FIG. 7 is an axially rear fastening portion of a balancing weight. -
FIG. 8 is a type of perspective part sectional view of a balancing weight on a rotor blade, the balancing weight having an axially rear fastening portion in correspondence withFIG. 6 . - The representations selected in the figures are rather sketch-like and are intended to illustrate the design of balancing weights. The drawings do not have the quality of dimensionally correct technical drawings. This relates, in particular, to certain perspective distortions or inaccuracies in the lines.
- In a simplified and schematic representation,
FIG. 1 shows a radially outer portion of arotor blade 10 and ashroud 12 associated therewith.Shroud 12 features anaxial projection 14.Projection 14 is configured in the area of axialleading edge 15 ofrotor blade 10. Afirst fastening portion 16 of a balancingweight 18 is hooked onto the radial outer side ofprojection 14. Starting from anunattached end 20,first fastening portion 16 is repeatedly bent, and then merges into amiddle portion 22.Middle portion 22 extends along the shroud and along the suction side ofrotor blade 10. -
FIG. 2 shows balancing weight 18 ofFIG. 1 in a simplified, perspective view. Besides the already mentionedfirst fastening portion 16 andmiddle portion 22 contiguous thereto, balancingweight 18 features asecond fastening portion 24. In the installed state of balancingweight 18,second fastening portion 24 is situated axially to the rear in each particular case and is couplable to an axial trailing edge of a shroud. At 26,middle portion 22 is twisted along axial direction AD (longitudinal direction of strip-type middle portion 22), here, exemplarily by approximately 90°. Thistwisted region 26 may also be referred to astorsion region 26.Middle portion 22 essentially extends along axial direction AD. First fastening portion essentially extends along circumferential direction CD.Second fastening portion 24 essentially extends in radial direction RD. In the representation inFIG. 2 ,second fastening portion 24 is situated in a first position relative tofirst fastening portion 16.Second fastening portion 24 assumes this first relative position when the balancing weight is not yet fastened to the shroud of the rotor blade. Thus,FIG. 2 shows an uninstalled state of balancingweight 18. In other words, balancingweight 18 features the configuration shown inFIG. 2 prior to the mounting thereof on a rotor blade. -
FIG. 3 showsrotor blade 10 ofFIG. 1 in a simplified, perspective view, axially from the rear. In comparison to the state ofFIG. 2 (uninstalled state of the balancing weight),middle portion 22 of balancingweight 18 no longer shows atwisted region 26. There is no twisting ofmiddle portion 22 becausesecond fastening portion 24 has been swiveled clockwise relative to the direction of view inFIG. 2 andFIG. 3 . This swiveling or twisting moves second fasteningportion 24 into a second position relative to first fastening portion 18 (not visible inFIG. 3 ). In this second relative position,second fastening portion 24 is coupled to anaxial trailing edge 28 ofshroud 12. - By considering
FIG. 1 through 3 together, even the process of attaching a balancingweight 18 may be easily understood. A balancingweight 18 is axially introduced byfirst fastening portion 16 thereof between two rotor blades and, specifically, axially from the rear.First fastening portion 18 is then hooked onto axial leadingedge 15 ofshroud 12, in particular ontoprojection 14. Upon positioning offirst fastening portion 18,middle portion 22 may be guided alongshroud 12.Second fastening portion 24 is then still situated in the first position illustrated inFIG. 2 relative tofirst fastening portion 16. In the region ofaxial trailing edge 28 ofshroud 12,second fastening portion 24 may then be grasped by a suitable tool and twisted accordingly.Twisted region 26 of middle portion (FIG. 2 ) is again opened, respectivelymiddle portion 22 is again brought into an essentially torsion-free, respectively planar orientation (FIG. 3 ). Thus, a balancing weight of this kind may be readily introduced along a rotor blade and fastened to the shroud of the rotor blade by a deformation of the balancing weight; in the present example, by a deformation of the middle portion. - As is apparent from
FIGS. 1 and 3 ,first fastening portion 16 is formed in a way that allows balancingweight 18 to be secured in radial direction RD, circumferential direction CD and axial direction AD. In second position thereof relative tofirst fastening portion 16,second fastening portion 24 additionally secures the balancing weight in axial direction AD and in radial direction RD. Thus, balancingweight 18 is securely installed onshroud 12. -
FIG. 4 shows an illustration similar to that ofFIG. 3 ; in addition tosecond fastening portion 24, which is likewise illustrated here in the second position relative tofirst fastening portion 16, balancingweight 18 featuring a securingportion 30. Additional securingportion 30 constitutes a securing in axial direction AD and rests against axial trailingedge 28 ofshroud 12. In the example ofFIG. 4 , securingportion 30 andsecond fastening portion 24 form two side portions that extend slightly obliquely relative to each other starting frommiddle portion 22. -
FIG. 5 shows an illustration similar to that ofFIG. 4 ; in the case of balancingweight 18, securingportion 30 andsecond fastening portion 24 having a continuous design along trailingedge 28 ofshroud 12. In this example, securingportion 30 also serves as securing in axial direction AD. - In
FIGS. 4 and 5 , balancingweight 18 may likewise feature atwisted region 26 in an uninstalled state, analogously to the balancing weight inFIG. 2 . Alternatively, in the case of the balancing weights ofFIGS. 4 and 5 , it may be considered that onlysecond fastening portion 24 is bent downwardly in the first relative position and, in the case of installation, bent correspondingly upwardly. -
FIG. 6 shows an illustration similar to that ofFIG. 1 ; adjoiningfirst fastening portion 16 on balancingweight 18, a hook-on portion 32 (blade coupling portion) being provided that is positioned in the region of an axial leading edge ofrotor blade 10. This hook-onportion 32 provides securing in axial direction AD and circumferential direction CD, whilefirst fastening portion 16 is used for securing balancingweight 18 in axial direction AD and radial direction RD. In this embodiment,first fastening portion 16 is bent around leadingedge 15 of the shroud and not looped aroundprojection 14, as inFIG. 1 . -
FIG. 7 shows an alternativesecond fastening portion 24 of a balancing weight. In a first position thereof relative to first fastening portion, second fastening portion is essentially planar in accordance withFIG. 7A . The second fastening portion features elongated holes orslots 36 that extend transversely to the longitudinal extent thereof If a balancing weight having such asecond fastening portion 24 is attached to the shroud of a rotor blade, the second fastening portion may be deformed or bent over in the area ofelongated holes 36 once the balancing weight is introduced, and the first fastening portion is hooked on, allowing it to be bent around axial trailing edge (28) (FIG. 1, 3, 4, 5 ) of the shroud. The bending process is illustrated step by step inFIGS. 7B and 7C . In the region ofelongated holes 36, the process of deforming or bendingsecond fastening portion 24 is simplified due to the structural weakening of the otherwise strip-type fastening portion 24. As illustrated inFIG. 7C ,second fastening portion 24 has been bent over or deformed twice in the second relative position. Thus, second fastening portion assumes a different relative position than in first relative position (FIG. 7A ). - A
web 38 is formed between the twoelongated holes 36. In accordance with the illustration ofFIG. 8 , thisweb 38 may be adapted to the contour along anaxial trailing edge 28 of the shroud. In the illustrated example,web 38 is deformed in axial direction AD toward the trailing edge ofshroud 12, allowing it to rest against the multiply curved contour of the shroud. This makes it possible to form a type of interlocking connection. It should be appreciated that second fastening portion inFIG. 8 is merely depicted as a stylized sectional view to provide a better illustration ofdeformed web 38. It is clear thatmiddle portion 22 is actually joined tosecond fastening portion 24, even when this is not shown inFIG. 8 . In the axially leading region thereof, balancingweight 18 ofFIG. 8 has a design similar to that ofFIG. 6 and features a hook-onportion 32. - Balancing
weight 18 presented here generally has a type of metallic strip design; as is apparent inFIG. 2 , this strip being bent or deformed in different directions, so that the various portions are formed that are then used for mounting on the shroud. - The specific embodiments of balancing
weight 18 shown with reference toFIG. 1 through 8 , in particular of the various embodiments offastening portions portion 30 or hook-onportion 32 ormiddle portion 22, with or without twistedregion 26, may be combined with one another in any way desired. Thus, for example, afirst fastening portion 16 shown inFIG. 1 , that is hooked onto aprojection 14 ofshroud 12, may feature asecond fastening portion 24 in accordance withFIG. 7 . Every combination that is derivable from the figures leads to a further specific embodiment of the balancing weight according to the present invention, even when all possible combinations are not explicitly shown. - The balancing weight presented here makes possible altogether a simple mounting of the balancing weight along a rotor blade and on the shroud of this one rotor blade; it being necessary to deform the middle portion or/and the second fastening portion, respectively, for final completion of the fastening to bring the second fastening portion into the second position thereof relative to the first fastening portion.
- 10 rotor blade
- 12 shroud
- 14 projection
- 16 first fastening portion
- 18 balancing weight
- 20 unattached end
- 22 middle portion
- 24 second fastening portion
- 26 twisted region
- 28 axial trailing edge
- 30 securing portion
- 32 hook-on portion
- 34 axial leading edge rotor blade
- 36 elongated hole
- 38 web
Claims (16)
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
DE102016210454.3A DE102016210454A1 (en) | 2016-06-14 | 2016-06-14 | Balancing weight for a blade of a turbine stage |
DE102016210454.3 | 2016-06-14 |
Publications (1)
Publication Number | Publication Date |
---|---|
US20170356293A1 true US20170356293A1 (en) | 2017-12-14 |
Family
ID=59030849
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US15/617,112 Abandoned US20170356293A1 (en) | 2016-06-14 | 2017-06-08 | Balancing weight for a rotor blade of a turbine stage |
Country Status (4)
Country | Link |
---|---|
US (1) | US20170356293A1 (en) |
EP (1) | EP3258064B1 (en) |
DE (1) | DE102016210454A1 (en) |
ES (1) | ES2779004T3 (en) |
Citations (9)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US5011374A (en) * | 1987-11-17 | 1991-04-30 | General Electric Company | Method and apparatus for balancing turbine rotors |
US20020085913A1 (en) * | 2000-12-06 | 2002-07-04 | Mathieu Bos | Guide vane stage of a compressor |
US20050265845A1 (en) * | 2004-05-28 | 2005-12-01 | Darek Zatorski | Method and apparatus for balancing turbine rotors |
DE102004026365A1 (en) * | 2004-05-29 | 2005-12-22 | Mtu Aero Engines Gmbh | Turbine engine e.g. aircraft engine, outer cover band compensating device, has plate-shaped section including U-shaped area, where device is made of a plastically deformed wire-shaped unit whose cross section has round form |
US20110223007A1 (en) * | 2010-03-15 | 2011-09-15 | Hammel Christian | Radial fan wheel arrangement |
US20120087794A1 (en) * | 2009-03-09 | 2012-04-12 | Avio S.P.A. | Rotor For Turbomachines With Shrouded Blades |
US20140348655A1 (en) * | 2013-05-27 | 2014-11-27 | MTU Aero Engines AG | Balancing body for a continuous blade arrangement |
US20150233389A1 (en) * | 2012-09-18 | 2015-08-20 | Emb-Papst Mulfingen Gmbh & Co. Kg | Impeller having balance compensation |
US9638214B2 (en) * | 2011-10-12 | 2017-05-02 | Ebm-Papst Mulfingen Gmbh & Co. Kg | Balancing weight for a fan wheel |
-
2016
- 2016-06-14 DE DE102016210454.3A patent/DE102016210454A1/en not_active Withdrawn
-
2017
- 2017-06-08 EP EP17174881.7A patent/EP3258064B1/en active Active
- 2017-06-08 ES ES17174881T patent/ES2779004T3/en active Active
- 2017-06-08 US US15/617,112 patent/US20170356293A1/en not_active Abandoned
Patent Citations (10)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US5011374A (en) * | 1987-11-17 | 1991-04-30 | General Electric Company | Method and apparatus for balancing turbine rotors |
US20020085913A1 (en) * | 2000-12-06 | 2002-07-04 | Mathieu Bos | Guide vane stage of a compressor |
US20050265845A1 (en) * | 2004-05-28 | 2005-12-01 | Darek Zatorski | Method and apparatus for balancing turbine rotors |
DE102004026365A1 (en) * | 2004-05-29 | 2005-12-22 | Mtu Aero Engines Gmbh | Turbine engine e.g. aircraft engine, outer cover band compensating device, has plate-shaped section including U-shaped area, where device is made of a plastically deformed wire-shaped unit whose cross section has round form |
US20120087794A1 (en) * | 2009-03-09 | 2012-04-12 | Avio S.P.A. | Rotor For Turbomachines With Shrouded Blades |
US20110223007A1 (en) * | 2010-03-15 | 2011-09-15 | Hammel Christian | Radial fan wheel arrangement |
US9638214B2 (en) * | 2011-10-12 | 2017-05-02 | Ebm-Papst Mulfingen Gmbh & Co. Kg | Balancing weight for a fan wheel |
US20150233389A1 (en) * | 2012-09-18 | 2015-08-20 | Emb-Papst Mulfingen Gmbh & Co. Kg | Impeller having balance compensation |
US10018206B2 (en) * | 2012-09-18 | 2018-07-10 | Ebm-Papst Mulfingen Gmbh & Co. Kg | Impeller having balance compensation |
US20140348655A1 (en) * | 2013-05-27 | 2014-11-27 | MTU Aero Engines AG | Balancing body for a continuous blade arrangement |
Also Published As
Publication number | Publication date |
---|---|
EP3258064A1 (en) | 2017-12-20 |
ES2779004T3 (en) | 2020-08-13 |
DE102016210454A1 (en) | 2017-12-14 |
EP3258064B1 (en) | 2020-02-19 |
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